Contact broadleaf herbicide with no off-gassing?

General Fruit Growing
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If weeds are overtaking the grass in aisles between fruit trees… Are there any broadleaf herbicides safe to use to control them?

Probably not either of these (various topics on this forum serve as the cautionary tale):
Dicamba and 2,4-D can also move off-target as a gas. They are among the relatively small number of pesticides that are highly prone to volatilize (turn into a gas). A spike in air temperature can cause these herbicides to turn into a gas even after they have been successfully applied to target surfaces. As temperature inversions form, pesticide vapors lingering in the atmosphere can be pulled back down to the surface where they can cause damage.

Also not something with a mode of action through the roots.

Which seems to leave only a leaf/contact herbicide, which doesn’t volatilize. What would that be if such exists? What do you feel is the “best” if there are multiple options?

Thanks.

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Interesting subject. I would like to find some other options as well.

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These appear to be marketed for just this purpose, but are 2,4-d:

https://www.albaughllc.com/us/agriculture/crop-protection/herbicides/listings/orchard-star-

Hmm

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I’ve lost three trees of five from my earliest planting in 2007. These were/are all located along my property line.

Scion Root Last Crop
Wolf River B9 2021
Golden Russet B9 2017
Sweet 16 B9 2021
Honey Crisp B9 2023
Fireside M26 2023

Golden Russet failed under crop in 2018. Sweet 16 failed to leaf out in 2022. The central leader died and I removed it from Wolf River last fall, and the rest of the tree failed to leaf out this spring.

Was it disease? I grafted Kingston Black to Wolf River, Golden Russet, and Ellison’s Orange. Ellison’s Orange was planted in 2008 and has leafed out, but the Kingston Black branch has not.

Was it herbicide carryover? I accepted grass clippings for a couple of years from a neighbor not on the property line. The clippings were dumped principally on Wolf River, Golden Russet and Sweet 16, but I distributed the clippings to Honey Crisp, Fireside, and other trees planted between 2008 and 2009 without obvious ill effects. I have since switched to plastic mulch.

Was it a polar vortex? When Wolf River was slow to leaf out and set tiny blossoms in 2020, I sent pix of it to the County Extension Agent who forwarded them to a state fruit-tree specialist. They presumed the tree had been set back by winter weather. I have pix showing snow cover on the ground under the three trees that died while it has melted from the rest of my yard. There is a bit of a low-angle shadow from trees two yards over.

Was it juglone? Those trees casting the shadow are walnuts.

Is it senescence? Dwarf apples should live longer than 17 years, shouldn’t they?

Is it herbicide contamination of the ground along the property line? Honey Crisp and Fireside seem unaffected. I have not noticed the characteristic damage to foliage caused by volatile herbicides. However, another apple and a couple of persimmons I planted to replace the failed trees have likewise failed to prosper. In fact one of the persimmons is really late to leaf out this year.

… so I have many suspicions and herbicide contamination is among them. Herbicides used on the property line would potentially affect my trees growing there. Herbicides used there might persist for several years. I have no knowledge that herbicides have been used, though, or what they may have been.

It would worry me to use broad-leaf herbicides inside my orchard for fear of prolonged effects on my trees without understanding whether the herbicides were appropriate for lawn use in town and what level of persistence they were supposed to have.

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If you use 2,4-D, make sure it’s the 2,4-D Amine formulation. These are less volatile. I have sprayed my lawn for broadleaf weeds with 2,4-D amine numerous times, feet away from my garden, small trees, raspberries. I’ve never had any of them be affected.

Mix to the label directions, on a low wind day. Choose a spray nozzle/pressure with larger droplet size, not a fine mist. Can add some surfactant to the mix to improve wetting and absorbtion into the weed leaves.

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I haven’t heard of the group 2 ALS inhibitors as drift risks, they would be a good choice. I’ve used Matrix (halosulfuron) in a vineyard setting with good results.

Glufosinate is another option-- it is non selective but seems to be harder on broadleaf weeds than perennial grasses.

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Great info, thanks! I did not know the formulation mattered in this regard…

Looks like SpeedZone which I had purchased and used in my yard, but steered well clear of anything edible. Is an Ester formulation… So perhaps not it.

Again, thanks.

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Thanks for this info as well. I had been reading about the various active ingredients to see if anything sounded like it might be appropriate.

Glusofinate is interesting sounding, almost like it’s the opposite of Glyphosate. Which IME will kill grasses even at an incredibly low doses, while barely affecting anything broadleaf.

Non-selective seems wrong but could still work just fine if it only barely effects perennial grasses. Of which I have been trying to get Creeping Red Fescue healthy enough to out-compete the weeds. Difficult with just how determined they are!

Thanks.

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All of the group 4 herbicides (2,4-D, MCPA, Dicamba, etc) are volatile and subject to gassing off. Spray them in the morning when the ground is cooler than the air above it. If you use them late in the day when the ground is warmer than the air above it - that is when they will rise up and travel. I like glufosinate as a broad spectrum weed killer in the orchard. It can kill fruit trees, but not as near as quickly or easily as glyphosate. In my experience it is weaker at killing annual grasses(like volunteer wheat in a liberty link canola field) but quite capable of killing perennial grasses. Bromoxynil is a contact herbicide. Sold here in Canada as Pardner and as a co-ingredient in Buctril M and Infinity. But I have never seen it marketed in a consumer size format.

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I’ve only recently started using glufosinate and so far I’m liking it.

I try to use cultural practices to minimize spraying overall, but my go-to for when I do need herbicides is glyphosate. It was really struggling to adequately control bermuda grass runners, especially since those runners often are close enough to or even mixed in with perennials that I don’t want to kill. With glyphosate being systemic, I have to stay pretty far away from the perennials incase of over-spray. But mostly the glyphosate just wasn’t killing the bermuda grass reliably unless I hit it multiple times.

With glufosinate, since it’s mostly a contact herbicide, I feel a lot more comfortable spraying closer to the perennials–if they happen to lose a few leaves or stems it’s fine, they’ll recover soon enough. And it just seems to be much better at killing bermuda grass, especially now that it’s warm out and presumably the method of action is much faster.

I don’t have much use for selective herbicides, and I don’t like the constraints imposed by dicamba, so I don’t use it, 2, 4-D, and the like, and as such can’t comment on their efficacy. I really don’t like preemergent herbicides (glyphosate, glufosinate, etc. break down rapidly in the soil, which significantly reduces their negative ecological and cultural impact, preemergents don’t by design) and don’t use them on principle. Granted, I also don’t need preemergents, since I mulch heavily and very, very rarely direct sow or otherwise leave the ground bare (except in my weed whacker strips).

A few of the weeds we have here have herbicide resistance, but I’ve found that they tend to be fairly easy to control with mulch. There aren’t many weeds that are both mulch resistant and herbicide resistant. Bermuda grass has been the only one so far to come close to checking both those boxes.

Granted, most of my bermuda grass invasions are the result of falling behind on my week whacking, but that’s another story.

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